GAINESVILLE — As the critical time for citrus grove management begins this winter, the University of Florida is providing growers regular flower bud advisories. Such alerts provide critical information about the intensity and timing of citrus flowering.

Tripti Vashisth, a UF/IFAS associate professor of horticultural sciences, restarted the advisories Nov. 21 and will continue providing them every other week through the early spring.

Growers use this information to determine when to spray for Asian citrus psyllid control and when to stop using pesticide. This is so pollinating bees can be moved out of a sprayed area.

The psyllid can transmit Huanglongbing (HLB), also known as citrus greening disease, to citrus trees.

 
You can find the flower bud advisories on the UF/IFAS Citrus Research and Education Center (CREC) website at Flower Bud Induction — University of Florida, Institute of Food and Agricultural Sciences.

“This year is predicted to be an El Niño winter, which means more rain and possibly cooler temperatures,” said Vashisth, a faculty member at CREC who manages flower bud advisories. “All of this will affect flowering. So, we will have advisories every 15 days to provide accurate information on floral bud induction.”

Flower bud advisories are driven by the Citrus Flowering Monitor webapp which predicts date(s) when citrus trees will bloom based on observed and predicted weather patterns and other parameters (variety, expected yield, tree age and soil type).
 
Growers can enter parameters that are specific to their grove on their cell phone via the mobile version or computer to get a prediction. Knowing the bloom date is important for managing bloom and other related events. The Citrus Flowering Monitor also gives specific recommendations on how to manage flowering.

Growers should keep track of induction hours in their area and watch for projected warm periods from the weather services. Normal healthy trees could have their induction boosted by applying some drought stress.

Unfortunately, with HLB making root systems vulnerable, growers shouldn’t risk heavier preharvest fruit drop of the current crop by using water stress to prevent unwanted early vegetative growth and enhance induction of flowers.

Based on weather predictions, growers concerned about early flowering can apply gibberellic acid (GA) to prevent some early flowering. There are many things to consider when using GA. Please see the flower bud website for additional information before using GA.